Air flow surface cleaning apparatus



I AIR- FLOW SURF-ACE CLEANING APPARATUS 8 Sheets-Sheet 1 Fi led Aug.50', 1966 4 BERNARD w. YOUNG BY 5% MW Jim/4F ATTORNEYS i AilR FLOWSURFACE ,CLEANIZNG APPARATUS 7 Filed Aug. 1956 s Sheets-Sheet 2' e ,9INVENTOR BERNARD w. YOUNG mlmh/ iwmmm ATTORNEYS Ma 19, 1 910* "mum3,512,206

AIR FLOW SURFACE CLEANING APPARATUS Filed Au 56, 1966 a Sheets-Sheet 5INVENTOR Q BERNARD W. YOUNG ATTORNEYS B. W. YOUNG AIR FLOW SURFACECLEANING APPARATUS 8 Sheets-Sheet 4:

FiledAug. 30, 1965 INVENTOR BERNARD W. YOUNG mam May 19, 1970 B. w YOUNGAIR FLOW SURFACE CLEANING APPARATUS 8 Sheets-Sheet 5 Filed vAug. 30,1966 INVENTOR BERNARD W. YOUNG m at ATTORNEYS May 19, 1970 B. w. YOUNG 4I AIR FLOW SURFACE CLEANING APPARATUS 8 Sheets-Sheet "Filed Aug. 56,1966 w .m w: I; 3 3 J x58 5 M f I g Q g a Q u i. N z mm y r 8 g a 2 1 3mNo (a n mm v mm 1 3 A H a 8 a a r N Ql no om o o 3 Q S 3 o o H m Twm h1| v u o M mm 0 mm l h a mm mm m 5 M a0. o 3.9T Sm ATTORNEYS May'l9,1970 B. w.- YOUNG- '3,51f2,v206

' Filed Aug" so, 1966 AIR FLOW SURFACE CLEANING APPARATUS INVENTOR 46/41 45 43 BERNARD w. YOUNG ATTORNEYS ay 1 1 70 B. w. YOUNG 3,512,206

AIR FLOW SURFACE CLEANING APPARATUS Filed Aug. 30, 1966 8 Sheets-Sheet 8INVENTOR BERNARD W. YOUNG BY Mb, Milli/m wzwu ATTORNEYS United StatesPatent U.S. Cl. -346 17 Claims ABSTRACT OF THE DISCLOSURE An air flowsurface cleaning apparatus includes a pickup head mounted for movementin a path in the direction of cleaning progress over a surface to becleaned. A suction chamber within the pick-up head extends transverselyof said path. Air under pressure is-discharged through orifice means atan inclination forwardly and downwardly along a line adjacent atransverse edge of the suction chamber so as to be deflected from thesurface being cleaned into the suction chamber substantially throughoutthe entire Width of the suction chamber. The air is exhausted from oneend of the suction chamber so that air flows therein transversely of thecleaning path as Well as longitudinally thereof. 1

A pressure chamber receives air under pressure from the outlet of ablower, the air then being discharged under pressure through the orificemeans. The suction chamber and the pressure chamber are both of suchvarying cross section that the air pressure is substantially uniformfrom one end to the other of the respective chambers.

The pick-up head is provided with flexible ground engaging means whichsupport partof the pick-up head weight, the remainder of the weightbeing supported by resilient suspension means. I

-The air and entrained solids picked up from the surface are passedthrough solids'separation equipment including bafile means forprecipitating relatively large-or heavy objects or particles, and aspecial form of centrifugal mass-in-motion separator which removes fineparticles from the air stream, the cleaned air being recirculated to theblower intake.

This invention relates-t0 air flow surface cleaning apparatus, and moreparticularly to mobile equipment adapted to be moved over surfaces suchas roads, pavements, streets, air strips and the like for removingdebris and dust. Various apparatuses of this general Class have beenknown for some time. In one known type, a motorized vehicle is equippedwith rotary brushes which dislodge dirt from the surface being cleaned,and withsuction equipment for picking up the dirt and delivering it to.a collection bin or the like. In some such conntructions, the air withentrained dirt and debris is passed through filters or a bag in thenature of a vacuum cleaner bag for separation of the solids anddischarging of the air beyond the filters or bag. In theseconstructions, air is not recirculated, but fresh air in continuouslyused to suck up the dirt dislodged by the brushes. In other prior artconstructions, air is caused to flow over the surface being cleaned forpicking up dirt and debris, and is passed through solids separationequipment for removal of the solids from the air stream which is thenrecirculated and used again for passing over the surface.

The present invention relates still more particularly to this lattertype of air flow surface cleaning apparatus.

Factors which are important in the efiicient opeartion of such anapparatus are firstly the eflicient dislodging of dirt and debris fromthe surface being cleaned and picking it up without creating anundesirable dunt cloud surrounding the apparatus, and secondly theeffective removal of the dust, dirt and larger trash pieces from the3,512,206 Ice Patented May 19, 1970 air stream before it is recycled tothe dislodging and picking up zone.

An object of the present invention is to provide air flow surfacecleaning apparatus capable of performing these main functions, that isthe dislodging and picking up of dirt and trash and the separation ofdirt and trash from the circulating air, more efiiciently than hasheretofore been possible.

A more particular object of the invention is to provide air flow surfacecleaning apparatus including an improved form of dirt and trash pick-upequipment which is so constructed that a blast of air is delivered toimpinge uponthe surface being cleaned in such a direction as veryefiiciently to dislodge adhering trash or particles from the surface,and in which the air flow over the surface has multiple directionalcomponents so as uniformly to clean the surface and to discharge the airwith entrained solids for subsequent solids separation and recirculationof the air.

Other objetcs of the invention will become apparent from the followingdetailed description of a preferred embodiment, the appended claims, andthe accompanying drawings, in which:

FIG. 1 is a side elevational view of a truck carrying apparatusembodying the invention, the front part of the truck cab being brokenaway;

FIG. 2 is an enlarged scale vertical transverse section on the line 2-2of FIG. 1, with some parts at the right of the view being shown inelevation as seen from the rear of the apparatus;

FIG. 3 is an enlarged scale horizontal section on the line 3-3 of FIG.1;

FIG. 4 is a longitudinal vertical section on the line 4-4 of FIG. 2, therear part of the apparatus being broken away;

FIG. 5 is a reduced scale schematic vertical section on the line 5-5 ofFIG. 2, showing only a cylindrical dust separation and blower intakechamber and an appurtenant intake guiding baffie and a solids deflectingbaffle;

FIG. 6 is a view similar to FIG. 5, but with the section being taken onthe line 6-6 of FIG. 2;

FIG. 7 is a view similar to FIG. 5, but with the section taken on theline 7-7 of FIG. 2;

FIG. 8 is a perspective view from the rear of and above a solidscollection bin and housing, partly broken'away to show solids separationequipment Within the housing;

FIG. 9 is a horizontal section on the line 9-9 of FIG. 2, showing someof the internalconstruction of a pick-up head;

FIG. 10 is an enlarged scale vertical section on the line 10-10 of FIG.9;

FIG. 11 is an enlarged scale vertical section on the line 11-11 of FIG.9;

FIG. 12 is an enlarged scale vertical section on the line 12-12 of FIG.9;

FIG. 13 is an end elevation of a modified pick-up head;

FIG. 14 is a fragmentary vertical section on the line 14-14 of FIG. 4,showing parts of a spring suspension for the pick-up head in elevation;

a FIG. 15 is an enlarged scale detail fragmentary sectional view on theline 15-15 of FIG. 14;

FIG. 16 is a fragmentary elevational view of a pick-up 3 FIG. 20 is aview similar to FIG. 19, but showing the closure gate in its openposition.

GENERAL ORGANIZATION As shown in FIG. 1, apparatus generally designatedA embodying the invention is carried on a wheeled mobile equipment,specifically a motor truck T. The apparatus includes a frame 1supporting a housing H providing a solids collection bin SCB. A pick-uphead P is floatingly suspended from the frame 1 and extends transverselyto the direction of the path of cleaning progress or movement of thetruck over and adjacent to the surface to be cleaned.

A blower B is carried by the apparatus housing H at the left side of thelatter. In this description, references to the left side of theequipment apply to the side of the equipment at the left side of thetruck, that is the drivers side, whereas references to the right side ofthe equipment, of course, apply to the opposite side thereof.

The blower B is arranged to discharge air under pressure through apressure duct 2 to the pick-up head P which, as will be explained indetail below, is so constructed that the air under pressure is deliveredthrough orifice means in a forceful flow downwardly against the surfaceto be cleaned under the pick-up head and flows over that surface bothparallel to the direction of cleaning progress and transversely to thatdirection, being finally passed to the right side of the pick-up headfrom which it is exhausted through a suction or exhaust duct 3 anddelivered into the solids collection bin SCB which is of very largevolume. The air and entrained solids having reached the large volumesolids collection bin slow down, so to speak, permitting a major part ofthe entrained solids to drop to the bottom of the bin. The air, stillcontaining some entrained solids, then is delivered to the blower intakefor recirculation through the pick-up head. In the course of its flowfrom the right end of the pick-up head, the air encounters and passesthrough or beyond solids separation equipment which effects supplementalsolids separation, removing from the air stream particles, mainly veryfine dust or light trash which does not readily drop out of therelatively slowly moving air in the large volume collection bin.

The housing H has a rearwardly and downwardly slanting bottom as shownin FIGS. 4, 8, 19 and 20, and a rear wall which is provided with a dumpopening 4 normally closed by a closure gate 5 hinged to the housing at6. The closure gate 5 is movable to open position by power operatedmeans comprising, on each side of the housing, a hydraulic cylinder 7pivoted at one end to the housing, and an associated piston rod 8 whichis pivoted to one end of a knuckle linkage 9, the other end of which ispivoted to the gate 5. When the piston rod 8 is retracted into thecylinder 7, it will pull the linkage 9 to swing the closure gate 5 tothe position shown in FIG. 19. The gate 5 may be swung to its open ordumping position by admitting fluid under pressure into the cylinder 7to extend the piston rod 8 and move the parts to the positions shown inFIG. 20.

To ensure that substantially all solids collected on the bottom of thebin SCB will be removed when the gate 5 is opened, a raker plate 10 ismounted to extend transversely across the bin bottom and to rest uponthe bottom. Two links 11 pivoted at their front ends to the raker plate10 and at their rear ends to the gate 5 pull the raker plate 10rearwardly toward the dump opening 4 in response to movement of the gate5 to its open position.

Arrows shown in the drawings indicate generally the directions of airflow in various parts of the apparatus.

PICK-UP HEAD FIGS. 1, 2, 3, 9, 10-, 11 and 12 illustrate theconstruction of the pick-up head P itself. The mounting of the pick-uphead, including its floating suspension, the arrangement for towing orpulling the pick-up head, and mechanism for raising the pick-up headclear of the ground to an inoperative position, is illustratedparticularly in FIGS. 1, 2, 3, 4, 14, 15 and 16.

The pick-up head P preferably is formed basically of sheet material. Theinternal construction of the pick-up head, which forms an important partof the present invention, is described in detail hereinafter. At thispoint, the description will be directed principally to the mounting ofthe pick-up head. The pick-up head is provided with two fore and aftextending bars 12 respectively located adjacent to the ends of the headas shown in FIGS. 2 and 3. The bars 12 are connected to the lower endsof springs 13, the upper ends of which are anchored to nuts 14, as bestshown in FIG. 15. The nuts 14 are received on threaded rods 15 whichextend upwardly through brackets 16 which are normally stationary, butwhich may be adjusted transversely as explained below. Above thebrackets 16, the rods 15 are provided with fixed collars 17 supported bythe brackets 16. By rotating the threaded rods 15 by handles 18, thevertical positions of the nuts 14 may be changed so as to apply varyingamounts of tension to the springs 13 when the pick-up head P is restingupon the surface to be cleaned. When the pick-up head is so positioned,part of its Weight is carried by the suspension springs 13 and theremainder of its weight is carried by the pick-up head itself in contactwith the surface. As will be explained hereinafter, the pickup head isequipped with flexible ground engaging elements. By varying thesuspension effect of the springs 13, the degree of flexing of theflexible elements on the pick-up head and the pressure exerted on thesurface by the flexing ground engaging elements may be controlled.

In order that the pick-up head may be shifted transversely of thedirection of cleaning progress, for example to position one of its endclose to a curb, the springs 13 and threaded rods 15 and appurtenantparts are mounted for transverse adjustment as best illustrated in FIGS.3, 4 and 14. A supporting slide 19 is mounted on a frame cross member 20having a forwardly extending inclined top flange 21. The slide 19 has atop part which rests upon the flange 21, a reversely turned flange whichextends under the flange 21 and a downwardly extending flange which liesagainst the top part of the cross member 20. The cross member 20 isprovided with a keeper plate 21a which fits against the back of thedownwardly extending flange of the slide 19. The arrangement is suchthat the slide 19 can be moved transversely on the cross member 20 whenthe weight of the pick-up head on the springs 13 and threaded rods 15 isrelieved. When, however, the springs 13 and threaded rods 15 are againcalled upon to carry part of the weight of the pick-up head, the cantingof the slide 19 relative to the cross member 20, flange 21 and keeperplate 21a locks the slide in its position of transverse adjustment.Movement of the slide 19 transversely is facilitated by a handle 22shown in FIG. 14.

As shown in FIGS. 1, 2, 3 and 4, the pick-up head P towed or pulled overthe surface to be cleaned by two connecting rods 23 pivoted at 24 toframe mounted brackets 25 and pivoted at 26 to the bars 12 on top of thepickup head P.

When the apparatus is to be transported without being used for cleaninga surface, the pick-up head should be raised clear of the ground so asto avoid unnecessary Wear and permit rapid transport. Operating meansfor raising the pick-up head to an inoperative position is illustratedin FIGS. 3, 4 and 16, in which is shown a cross shaft 27 mounted forrocking in bearings 28 carried by the frame. At its left end, the shaft27 is provided with a bell crank 29, and at its right end it is providedwith a bell 30. Chains 31 having their upper ends connected respectivelyto one arm of the bell crank 29 and to the arm 30 are connected at theirlower ends to the bars 12 on the top of the pick-up head P. Rocking ofthe shaft 27 counterclockwise as viewed in FIGS. 4 and 16, will lift thechains 31 and the pick-up head. The shaft 27 is rockable by means of ahydraulic cylinder 32 pivoted at 33 to the frame and an associatedpiston rod 34 connected to the depending arm of the bell crank 29.Extension of the piston rod 34 will rotate the shaft counterclockwise asrequired for raising the pick-up head clear of the ground, andretraction of the piston rod into the cylinder will lower the pick-uphead to be floatingly suspended by the springs 13.

Referring now more particularly to the construction of the pick-up headas illustrated in FIGS. 1, 2, 9, 10, 11 and 12, the head is of generallybox-like structure which may be formed' of sheet material, the partsbeing joined together in any suitable manner as by conventionalfastening devices, not shown, or by welding. The head comprises a topwall 35, a front wall 36, a rear wall 37, a left end wall 38, and aright end wall 39. The bottom of the pickup head, considered in itsentirety, is open.

A generally horizontal but definitely sloping partition wall 40, spacedbelow the top wall 35 and above the bottom of the head P, extends fromthe left end wall 38 toward the right end of the head adjacent to whichit merges with a transition 41 connected to the suction duct 3 as shownin FIG. 2. As shown in FIG. 2, the partition or wall 40 slopes upwardlyfrom the left end of the head P, that is the head end under the pressureduct 2, toward the top wall 35. Consequently, the cross sectional areabelow the sloping wall 40 increases from left to right and vice versedecreases from right to left.

As shown in FIGS. and 12, the sloping partition wall 40 is joined alongits front edge to the front wall 36 of the head P, but the rear edge ofthe wall 40 is turned down to form a flange 42 which is spaced forwardlyof the head rear wall 37. A tube 43, which is welded or otherwiseconnected to the end walls 38 and 39 for strengthening the structure, isdisposed below the partition 40 and just in front of the downwardlyturned flange of the latter. The lower part 44 of the head rear wall 37is turned forwardly' at an inclination at 44 and terminates in closelyspaced relation to the flange 42 and tube 43 to provide a slot-likenozzle opening 45 through which air is caused to flow under pressurefrom above the partition 40 to the space between the latter and thesurface being cleaned. A reinforcing angle member 46 is secured to thehead structure to extend alongside the inwardly turned or inclined part44 for maintaining the latter in definitely spaced relation to theflange 42 and thus maintain the orifice opening 45 constant. 1

A vertical partition wall 47 is mounted within the head P between thetop wall thereof and the sloping horizontal partition wall 40. As shownin FIG. 9, the vertical parition wall 47 is inclined with respect to thefront and rear walls 36 and 37, the left end of the vertical wall 47being joined to the front wall 36 adjacent to but spaced from the leftend wall 38, and the right end of the partition wall 47 being joined tothe transition 41 underlying and being connected to the suction duct 3.The inclined vertical wall 47 divides the space between the top wall 35and the sloping horizontal partition wall into two separate chambers.One of these chambers is defined by the front wall 36, the inclined wall47, the horizontal wall 40, the top wall 35, and the transiton 41. Thisparticular chamber has no function in the operation of the pick-up head.The second chamber is at the rear of the inclined vertical partiton 47(to the bottom of this partition as shown in FIG. 9), and constitutes apressure chamber PC which receives air under pressure from the duct 2.

' Air under pressure in the chamber PC is discharged downwardly and at aforward inclination through the slotlike orifice to impinge upon thesurface being cleaned so as to loosen dirt and direct it forwardly underthe horizontal partition 40 which serves as the top of a suction chamberSC. With reference to FIGS. 10, 11 and 12, the flange 42 and tube 43 aredisposed horizontally between the orifice 45 and the suction chamber SC,parallel to the orifice, immediately adjacent to the suction chamberrear edge and immediately in front of the orifice means 45, and togetheract as air guiding means to guide the air stream to flow horizontallyinto the suction chamber, entering 6 v the latter at a level spacedbelow the suction chamber top wall 40. This suction chamber is ofuniform width fore and aft throughout its extent from end to end of thepickup head P. However, because of the slope of the wall 40 at the topof the suction chamber SC, this chamber increases in height and hence incross section from the left end of the pick-up head P to the right endof the head.

In operation, air delivered under pressure by the blower B flowsdownwardly through the pressure duct 2 and a transition 48 into the leftend of the pressure chamber PC. Air flow direction changing vanes 49 atthe bottom of the transition 48 turn the air flow smoothly from verticalto horizontal to flow toward the right in the pressure chamber PC. Therebeing air under pressure throughout the pressure chamber PC, air isdischarged through the slot orifice 45, all of the air discharged by theorifice flowing downwardly and forwardly into the suction chamber SC,loosening dirt and trash from the surface being cleaned and carrying thedirt and trash into the suction chamber. Air with entrained solids iswithdrawn from the right end of the suction chamber SC through thetransition 41 and suction duct 3 to be delivered to the solidscollection bin SCB and subjected to solids separation treatment byequipment to be described hereinafter. Since air enters the suctionchamber in a generally forward direction from the orifice slot 45, andsince air is withdrawn from the suction chamber at its right end, thereis a compound flow of air in the suction chamber, that is air flowhaving directional components both transverse to the direction ofcleaning movement and approximately parallel to that direction. Thecompound directional flow of air over the surface being cleaned has beenfound to be much more effective in loosening dirt and trash from thesurface than a flow of air substantially in one direction only. Aparticle of trash adhering to the surface being cleaned may be and oftenis more easily dislodged from the surface if attacked by a current ofair passing in one direction than by a current of air passing in any ofa number of other directions. By virtue of the complex air flow, that isflow with dilferent directional components, in the suction chamber SCand over the surface being cleaned, all adhering particles of trash anddirt will sooner or later be subjected to air flow in the direction bestcalculated to dislodge the particles.

It is desirable that when the air stream flows from the right end of thesuction chamber SC upwardly into the transition 41, its change of flowdirection from horizontal to vertical should be accomplished smoothly soas to avoid eddy currents and agitation which might permit heavier trashparticles to drop back onto the surface being cleaned. For this purpose,a flow direction changing vane 50 is mounted near the bottom of theright end of the pick-up head P below the transition 41. As shown inFIG. 3, the vane 50 is spaced diagonally downwardlyoutwardly from thejunction of the suction chamber top wall 40 with the portion of the duct2 which is spaced inwardly from the suction chamber end extremity, atthe right in FIG. 3, the cross sectional area of the space between thevane 50 and the aforesaid junction being less than the cross sectionalarea of the exhaust duct 2 above the suction chamber SC. A bafile 51extends inwardly from the right end wall 39 part way under the vane 50to prevent any large pieces, for example rocks, from being drawnupwardly and becoming lodged between the direction changing vane 50 andthe end wall 39.

The pick-up head P is equipped with marginal flexible ground engagingcurtains which Serve to enclose the sides and ends of the suctionchamber SC and to scrape the surface being cleaned to assist inloosening dirt for being picked up in the air stream flowing in thesuction chamber. As shown in FIGS. 10, 11 and 12, a front curtainmounting plate 52 is secured to the front wall 36 of the head P andsupports a curtain assembly comprising an outer or front component 53and an inner or rear component 54 spaced from the front component 53."Preferably, the front component 53 is formed of a continuous sheet offlexible material such as heavy rubber or rubber substitute, webbing orthe like, and the inner component 54 is preferably constituted by anassembly of individual flexible fingers somewhat in the nature of heavybrush bristles. Units of the kind shown in FIGS. 17 and 18, which may beconstituted by flexible plastic fingers, serve this purpose well.

Secured to the rear wall of the pick-up head P is a rear mounting plate55 which supports a curtain assembly comprising an outer component 56and an inner component 57. The component 56 may be constituted by solidsheet of flexible material such as the component 53 at the front of thehead, and the inner component 57 may be constituted by a curtain ofindividual flexible fingers such as the fingers 54. In both curtainassemblies, the inner curtain components are spaced from the outercurtain components.

At the left end of the pick-up head is an end curtain 58 preferablyconstituted by closely contiguous individual flexible fingers, and atthe right end of the pick-up head there is a curtain 59 of similarconstruction. Both end curtains 58 and 59 project forwardly at 58a and59a beyond the front wall 36 of the pick-up head P, the arrangementbeing such that the forwardly extending curtain portions 58a and 59ainhibit the rolling or flow of trash lengthwise of the leading frontcurtain component 53 beyond the ends of the pick-up head. Thus, theextended side curtains 58a and 59a hold or confine such iarger trashpieces to roll or be pushed along in front of the outer curtain 53 untilin time such pieces find their way under the front curtain 53 so thatthey may be picked up by the suction air stream and carried out throughthe transition 41 and delivered to the solids collection bin SCB.

The pick-up head P is surrounded by the flexible marginal curtainelements which contact the ground and bear part of the weight of thepick-up head, the remainder of the weight being carried by the springs13 as previously explained. The marginal curtain elements partially sealthe suction chamber at its bottom so that the desired flow of airthrough the pick-up head is maintained. Being flexible, the curtains canbe lifted locally by relatively large pieces of trash such as cans andbottles, which are thereby enabled to move into the suction chamber andbe carried away by the air stream. The use of flexible individual fingercurtains 'm at least some of the curtain components is usually desirablesince these components are particularly effective in assisting theloosening of adhering dirt. Although the fingers have spaces betweenthem, they nevertheless additionally provide curtains preventinguninhibited or unrestricted air flow.

FIG. 13 shows a modified arrangement of curta ns particularly adaptedfor use in removing very light trash, such as leaves, from surfaces tobe cleaned. The basic pick-up head structure P shown in FIG. 13 isessentially similar to the pick-up head structure described above.However, in the FIG. 13 arrangement, the rear curtain assembly includesa plate 60 which mounts curtain components 61 and 62 essentially similarto the previously described curtain components 56 and 57. At the frontof the pick-up head shown in FIG. 13, a mounting plate 63 is secured tothe head and extends forwardly and upwardly so as to mount curtains 64and 65 of greater vertical extent and spaced forwardly from the pick-uphead P further than the curtains 53 and 54 described with reference toFIGS. 10, 11 and 12. Because of the mounting of the curtain components64 and 65 substantially out in front of the pick-up head P, and furtherbecause of the greater height of the curtain components 64 and 65,leaves and like trash may more easily enter between the components 64and 65 and pass into the suction chamber SC.

Briefly reviewing the operation of the pick-up head, air under pressuresupplied by the blower B is delivered downwardly through the pressureduct transition 48 at the left of the pick-up head and is turned by thevanes 49 to flow toward the right into the pressure chamber PC. Airunder pressure in the pressure chamber flows downwardly through theslot-like blast venturi orifice 45 continuously throughout its length.The rear wall part 44 defin'mg the rear of the blast venturi slot 45 isat such an inclination that the blast of air emerges from the orifice 45at an angle of approximately 45 to the surface being cleaned, thusimpinging forcibly upon the surface to loosen dirt and then flowingunder the tube 43 at the front of the nozzle opening 45 and entering thesuction chamber SC. The entire discharge from the orifice 45 is spacedbelow the top wall 40 of the suction chamber. Best results have beenobtained by positioning the tube 43 vertically so that the vertical areaof the space 66 between the bottom of the tube 43 and the surface beingcleaned is approximately 70%80% of the largest fiow area of the suctionoutlet 41. In most installations, the vertical distance of the bottomsurface of the tube 43 above the surface being cleaned is one inch totwo inches.

In order that the jet air stream of ribbon-like character passingdownwardly through the orifice 45 be substantially uniform in velocitythroughout the length of the orifice as so as to achieve substantiallyuniform cleaning of the surface, it is necessary for the pressure of theair in the pressure chamber PC to be substantially uniform from one endof the chamber to the other. This required substantially uniformpressure in the chamber PC is maintained as a result of the decreasingcross sectional area of the chamber PC from its left end adjacent to thepressure air delivery to its right end adjacent to the suction outlet.The progressive decreasing of the cross sectional area of the pressurechamber PC is due firstly to the inclination of the vertical partitionwall 47 which converges upon the wall 37 from left to right, andsecondly to the upward slope of the horizontal partition Wall 40 fromleft to right.

The upward slope of the horizontal wall 40 also causes the crosssectional flow area in the suction chamber SC to increase from left toright, that is from the end of the pick-up head P at which air isdelivered under pressure to the opposite end thereof from which air isexhausted by suction. Inasmuch as the amount of air flowing through thesuction chamber SC increases from left to right due to the dischargingof air continuously along and under the tube 43, the increasing of thecross sectional area of the suction chamber from left to righteliminates crowding of air at the right end of the suction chamber withincreased pressure, and maintains both the air pressure and air velocitysubstantially constant throughout the left to right length of thesuction chamber.

The provision of a space between each pair of front and back curtaincomponents, for example the space between the components 53 and 54,permits air to move both transversely and longitudinally between thecomponents. This facilitates collection of trash and ultimate deliveryof the trash into the suction chamber SC. Thus, if trash is temporarilytrapped between the curtain components 53 and 54, and if the curtain 54is lifted or deflected upwardly at one point, due, say, to encounteringa bottle or rock, dust and smaller pieces of trash can movelongitudinally of the curtains to the point at which the curtaincomponent 54 is lifted for ready entry into the suction chamber. Thetypes of curtains used both fore and aft of the pick-up head may bechanged so as best to suit different cleaning conditions, for examplevery dusty streets with little large trash, or streets on which there isconsiderable trash of the nature of cans, bottles, rocks or the like.

Under normal conditions, when a surface to be cleaned does not present avery large amount of very dry fine dust, the pick-up head P operateswith practically no dusting of the air outside of the head. However,when the surface to be cleaned is fouled with a great deal of very finedry dust and the atmosphere is very dry, there may be some tendency fordust stirred up by the curtains to rise into the atmosphere. This may besubstantially eliminated by spraying atomized moisture into thecirculating air. For this purpose, an atomizing nozzle 67 is shown inFIG. 3 mounted in the pressure transition 48. A hose 68 suppliesmoisture to the nozzle 67,from a tank 69, suitable means, not shown,being provided for delivering water to the nozzle 67 under atomizingpressure.

AIR RECIRCULATION AND SOLIDS SEPARATION The air recirculation and solidsseparation equipment for cleaning air and returning it to the blower Bis best illustrated in FIGS. 1-8. The blower B includes a housing 70 atthe left side of the housing H and a radial vane rotor or impeller 71mounted on a shaft 72 rotatable in bearings 73 carried by the housing70. The impeller 71 is driven by an internal combustion engine 74mounted on the frame 1 in front of the housing H through an enginepulley, not shown, and belts 75 and a pulley 76 on the rotor shaft 72,the pulleys and belts being enclosed in a casing 77,.

The blower discharges peripherally through a discharge transition 78 towhich the upper end of the pressure duct 2 is connected. The intake ofair to the blower is through an axial inlet 79 which is curved in crosssection as shown in FIG. 2 so as to direct inlet air to flow toward theblower axis of rotation as well as to flow generally in the direction ofextent of the blower axis.

Air flowing upwardly from the right end of the pick-up head P throughthe suction duct 3 passes through a transition 80 into an entrancepassage defined by a curved front and topwall81, the right side wall 82of the housing H, and a vertical inner wall 83 which extends rearwardlyfrom the front wall 81 but terminates short of the rear end of thesolids collection bin SCB. The forward part of the interior wall 83 isparallel to the wall 82 of the housing -H, but the rear portion of theinterior wall 83 is turned inwardly at'83a so that air emerging from thewalled passage may flow toward the center of the solids collection binSCB. Best results have been obtained with a construction in 'which therear edge of the interior wall portion 83a is inclined from its bottomupwardly and rearwardly as at 83b.

Air emerging from the passageway flows rearwardly into the large volumeof the solids collection bin SCB for delivery to the intake of theblower B in a particular manner described hereinafter. The heavierparticles of trash or dirt fall of their own weight into the bottom ofthe bin SCB without being passed on to the blower intake. However, somelight trash such as lint, leaves, bits of paper, strings or the like,frequently have a tendency to remain entrained in the air stream passingto the blower intake. The present invention provides for very eflicientremoval of such light debris. Disposed across the air inlet passagewayis a vibrating separator extending from side to side of the passage andprojecting downwardly from the passage top to just above the passagebottom. In the form shown, the vibrating separator is constituted by anassembly or complement of flexible reedlike elements 84 fixedly mountedat their upper ends at 85 and hanging downwardly unsupported so as to becapable of being deflected by the air stream and waving back and forthor vibrating in response to local air flow variations and being struckby fairly large pieces of trash. In operation, the reeds or similarelements, which may be formed of flexible plastic, are generallydeflected at their lower end portions as indicated by the curvatureshown in FIG. 4. Light pieces of trash are intercepted by the reeds andthe vibration of the latter causes the trash pieces to slip down thereeds and to be dropped from the latter onto the bottom of the entrancepassageway between the walls 82 and 83. The air stream flowing throughthe passageway moves the dropped light trash along the bottom of thecollection bin toward the rear thereof with no consequential entrainmentof the particles in the air stream passing to the blower intake.

Heavy trash pieces, for example rocks, cans, bottles or the like, arelikewise carried rearwardly through the pass sageway between the walls82 and 83. Since this passageway is at one side of the housing H, thatis the right side, there would be a tendency for such heavy particles tobe accumulated in one, the right, side of the collectionbin withconsequent overloading of the equipment on the right side. To preventthis, means are provided for deflecting the rearwardly flowing heavypieces toward the longitudinal center line of the bin SCB. In theillustrated and preferred embodiment, this deflecting means is providedby a rock deflector baffle generally designated 86 positioned in thepath of air flowing through and emerging from the flow passage betweenthe walls 82 and 83-83a. The deflector 86 includes a top plate 87 whichis inclined upwardly and inwardly toward the center of the bin SCB fromfront to rear, and a triangular end plate 88 for sup porting the rear ofthe inclined plate 87. As shown in FIG. 8, the top edge 87a of theinclined plate 87 is flush against the housing wall 82, and the loweredge 87b is flush with the bottom of the bin SCB.

Air, still containing a substantial amount of solids in the form ofentrained dust, sand particles or the like, moves from the upper part ofthe collection bin SCB forwardly for delivery to the blower intake. Itis important to separate the entrained dust, sand, or other fineparticles from the air before the latter reaches the blower intake. Inthe preferred construction, the air enters the blower by way of agenerally cylindrical chamber 89 defined by a circumferential wall 90and a closed right end constituted by part of the interior wall 83. Theleft end of the chamber 89 is in open communication with the blowerintake 79. As is clear from FIG. 2, the chamber 89 is axially alignedwith the blower impeller 71 and is axially much longer than itsdiameter. Air is caused to flow into the chamber 89 as explained below.

The bottom of the solids collection bin SCB is turned upwardly toprovide a transverse partition 91, the upper edge of which is joined tothe wall 90 along a line under the cylindrical chamber 89. The wall or.partition 91 therefore restricts flow of air from the bin SCB to beabove the chamber wall 90. Relatively large trash particles in the airflowing above the chamber wall 90 are intercepted by a screen 92 and arecaused to fall to the bottom of the bin SCB. However, some fineparticles may pass through the screen 92 and most of these should beremoved from the air stream before the air is returned to the blower.This removal is accomplished by movement of the air within the chamber89 in which the air both swirls around the chamber axis and travelsparallel to the axis from right to left as viewed in FIG. 2. Theswirling of the air in the chamber 89 is produced by introducing the airinto the chamber tangentially by a curved guide baffle 93 which directsthe air to flow with a venturi effect through a slot-like entranceopening 94 in the wall 90 tangentially into the chamber 89 and extendingsubstantially parallel to the chamber axis. The entrance opening 94extends the complete length of the wall 90 and chamber 89 so that airenters the chamber tangentially throughout its length. The air alsoflows axially with respectto the chamber due to the suction effect ofthe blower rotor 71. Thus, in total, the flow of air in the chamber 89is along a generally spiral path.

The circular motion component of the air and entrained dust particles,and even any drops of moisture present, within the chamber 89 causes theparticles to be thrown outwardly against the inside of the wall 90 to bedischarged tangentially through a solids discharge slit 95 extending thelength of the wall 90 and being angularly displaced about the axis ofthe chamber 89 from the entrance opening 94. Solids discharged throughthe slot 95 are intercepted by an overhanging solids deflecting bafile96 so as to be deflected downwardly and be deposited in the solidscollection bin SCB.

Controlling the flow of air into t e chamber 89 is important forachieving the most efficient solids separation. In the constructionshown, the curved guide baflle 93 is constituted by a smoothcontinuation of a part of the cylindrical wall 90, vthe continuationbeing of flatter curvature than the wall 90. In orderto ensure that amajor part of the air delivered to the chamber 89v will enter thechamber at the right end of the latter and con: tinuously from the rightend to its leftend adjacenttothe blower intake, the entrance opening 94tapers in circumferential width from a minimum width adjacent the blowerintake to a maximum width at the opposite end. In a typicalconstruction, the .entrance opening 94; tapers from .a width of abouttwo inches adjacent the blower. intake to a width of about six inchesvat the opposite, end. The tapering of the entrance opening 94 is .due toinclining one edge 94a thereof as shown in FIGS. 2 and 4 The decreasingwidth of the opening 94 from right to left is also shown schematicallyin FIGS. 5,6 and 7. The solids discharge slit 95 is ofmuch lessflow areathan the entrance opening 94, having approximately one-quarter inch widecircumferentially of the wall 90..

The dust separation effected by'the swirling of the air in the chamber89 utilizes a mass in motion principle according to which the rapdilyswirling masses of the dust particles are centrifugally moved outwardlyagainst the chamber wall 90 for discharge through the slit 95. Only verylight dust particles can remain in the air delivered to the blowerintake. The continued entrainment of a moderate amount of only verylight particles in the circulating air actually is advantageous in thatthe air containing such very fine particles is rendered heavier than aircompletely free of particles, with the result that the air dischargedthrough the blast venturi orifice 45 against the surface to be cleanedhas increased effectiveness in dislodging dirt for being picked up inthe suction chamber of the pick-up head P.

SUMMARY OF OPERATION The descriptions of different phases of operationdescribed above should render the operation of the complete apparatus asa unit readily apparent. However, a brief rsum of the overall operationmay be helpful. The closure gate being in closed position as shown inFIGS. 1 and 20, and the pick-up head P being lowered for engagement ofthe curtains with the surface to be cleaned, the truck T is progressedalong the line of cleaning while the blower B is driven by the engine74. Air delivered under pressure through the duct 2 and transition 48passes horizontally into the pick-up head pressure chamber PC from whichthe air is blasted downwardly at an inclination through the orifice 45to impinge upon the surface and loosen the dirt which is carried intothe suction chamber SC. Air with entrained trash flows through thesuction chamber SC to be exhausted through the transition 41 and duct 3and to flow through the passageway between the housing wall 82 and theinternal wall 83. In flowing through this passageway, relatively largebut light pieces of trash are intercepted by the reeds 84 and dropped tothe bottom of the solids collection bin SCB. Heavy pieces of trash aredeflected by the deflector 86 to move toward the center of the bin SCB.Air containing entrained dust moves slowly in the upper part of thelarge volume bin SCB so that much of the still entrained solid materialwill drop to the bottom of the bin. Air still containing some entrainedsolids will pass through the screen 92 which intercepts relatively largepieces ,which are dropped to the bottom of the bin. Air containing onlyfine entrained solids enters the cylindrical chamber 89 in which it issubjected to a swirling and axial flow, causing most of the remainingparticles to be discharged through the solids discharge slit 95, in-

terccpted by the bafile 96, and dropped to the bottomof the bin SCB.Relatively solids-free air, containing only a moderate amount ofextremely fine solids, is then receiv'ed by the blower intake andrecycled. Only under extremely dry conditions and when a great deal ofvery fine dust is to be picked up is it desirable to spray atomizedliquid through the nozzle 67. p The disclosed construction embodies theinvention in a preferred form, but it is intended that the disclosure beillustrative rather thandefinitive.

I claim:

1."In' an airflow surface cleaning apparatus, a pickup-head mounted-formovement in a path in a direction of lcle'ani ng'p rdg jes's' over andadjacent to the surfacetdbe cleaned said pick-up head having a suctionchamber within said pick up head extending transversely of said path,said pick-up .head having a top wall and being open at its bottom abovethe surface to be cleaned, narrow, continuously open slot orifice meansextending transversely of said path substantially all the way across thewidthuof-said path adjacent onlyone edge of said suction chamber whichedge is transverse to said path and is the rear edge. ,of said suctionchamber with respect to the direction of movement of said pick-up headin said path, and air guiding means disposed immediately adjacent saidsuction. chamber rear edge and immediately in front of said orificemeans and havingits bottom surface spaced above the; surface to becleaned and spaced below said suction chamber top wall and extendingtransversely parallel to said orifice means, said orifice means beingpositioned so that its entire discharge is spaced below said suctionchamber top Wall and its direction of discharge is inclined to saidsurface toward said suction chamber and forwardly in the direction ofmovement of said pick-up head in said path, whereby air under pressuredicharged by said orifice means impinges on said surface and isdeflected thereby and all of the air discharged from said orifice meansflows horizontally under said air guiding means and forwardly in thedirection of movement of said pick-up head in said path, and enters saidsuction chamber horizontally and spaced below said suction chamber topwall along a line extending transversely of said path; means fordelivering air under pressure to said orifice means for dischargethere'through and thence horizontally under said air guiding means intosaid suction chamber spaced below said'suction chamber top 'wall alongsaid transversely extending line; and exhaust means for discharging airfrom said suction chamber, whereby air is caused to travel in saidsuction chamber both parallel to and transversely to said pathsubstantially throughout the entire width of said suction chambertransversely of said path.

2. Apparatus according to claim 1 in which said orifice means and saidair guiding means provide a venturi, whereby air flows at a maximumvelocity when passing through the most narrow part of said venturi andis expanded upwardly with diminishing velocity into said suction chamberafter flowing under said air guiding means.

3. Apparatus according to claim 2 in which said pickup head comprises apressure chamber extending transversely of said path adjacent to saidsuction chamber, and in which said pressure chamber extendssubstantially throughout the length of said suction chamber.

4. Apparatus according to claim 3 in which said ex haust means isconnected to said suction chamber at one end thereof, and in which saidmeans for delivering air under pressure comprises a duct communicatingwith said pressure chamber at the end of said pick-up head opposite theend thereof at which said exhaust means is located. I

5. Apparatus according to claim 2 in which said exhaust means comprisesaduct extending upwardly from one end of said suction chamber, and inwhich air direction changing means is positioned within said pick-uphead at the junction of said duct and said suction chamber for turningair flowing horizontally in said suction chamber to flow upwardly intosaid duct, said air direction changing means comprising a vanepositioned adjacent to the extremity of said one end of said suctionchamber and lower than the top of said suction chamber at said one endthereof, said vane being spaced diagonally downwardly-outwardly from thejunction of said suction chamber top wall with the portion of said ductwhich is spaced inwardly from said suction chamber end extremity, thecross sectional area of the space between said vane and said junctionbeing less than the cross sectional area of said duct above said suctionchamber.

6. Apparatus according to claim 2 in which said air guiding means ismounted to be spaced above the surface to be cleaned by from about oneinch to about two inches.

7. Apparatus according to claim 2 including flexible ground engagingcurtains carried by said pick-up head along the perimeter thereof and inwhich said ground engaging curtains include end curtain portions atopposite ends of said pick-up head, said end curtain portions extendingin the direction of cleaning progress beyond said pick-up head wherebyto inhibit trash pieces which do not readily pass under the curtainportion at the front of said pick-up head from moving transverselybeyond and away from the latter.

8. Apparatus according to claim 2 including an apparatus frame, supportmeans mounted on said frame above said pick-up head for adjustment onsaid frame transversely to the direction of travel of said frame overthe surface to be cleaned, resilient means fioatingly suspending saidpick-up head from said support means for carrying part of the weight ofsaid pick-up head, and downwardly extending flexible ground engagingmeans carried by said pick-up head and supporting the remainder of theweight of said pick-up head, adjustment of said support means adjustingthe position of said pickup head relatively to aid frame transversely tosaid direction of travel.

9. Apparatus according to claim 1 in which said exhaust means comprisesa duct extending upwardly from one end of said suction chamber and inwhich the vertical area of the space between said air guiding means andthe surface to be cleaned is approximately 70%- 80% of the largest flowarea of said duct.

10. An air flow surface cleaning apparatus according to claim 1 in whichsaid means for delivering air under pressure includes a pressure chamberabove said suction chamber and separated therefrom by said suctionchamber top wall, said orifice means intervening between said pressurechamber and said suction chamber.

11. Apparatus according to claim 10' in which said exhaust meansdischarges air from one end of said suction chamber and in which saidsuction chamber decreases in cross section from said one end thereof tothe opposite end thereof.

12. Apparatus according to claim 11 in which the bottom wall of saidsuction chamber is provided by said surface to be cleaned and in whichsaid suction chamber top wall slopes downwardly from said one end ofsaid suction chamber to said oposite end thereof.

13. Apparatus according to claim 10- in which said exhaust meansdischarges air from one end of said suction chamber and in which saidpressure chamber increases in cross section from the one end of saidpressure chamber adjacent said one end of said suction chamber to theopposite end of said pressure chamber.

14. Apparatus according to claim 13 in which said pressure chamberincreases in height from said one end thereof to said opposite endthereof.

15. Apparatus according to claim 13 in which said pressure chamberincreases in width from said one end thereof to said opposite endthereof.

16. Apparatus according to claim 13 in which said pressure chamberincreases in both height and width from said one end thereof to saidopposite end thereof.

17. Apparatus according to claim 13 in which said pressure chamberincludes two vertical walls which converge upon each other toward saidone end of said pressure chamber.

References Cited UNITED STATES PATENTS 564,013 7/1896 Furnas l5346 X985,945 3/1811 Shea 15347 514,677 2/1894 Furnas. 1,211,902 1/1917Warner. 1,229,737 6/1917 Furnas 15340 X 3,054,130 9/1962 Ferraci 15-340FOREIGN PATENTS 588,799 2/ 1959 Italy.

ROBERT W. MICHELL, Primary Examiner US. Cl. X.R. l5340

